Roller cutter



April 7, 1931 w. L. CHILDS 1799576 ROLLER CUTTER Filed July 25, 1929 INVENTOR. BY ?Vu c A TTORNEY Patented Apr. 7, 1931 UNITED STATES PATENT OFFICE WILLIAM L. CHILDS, F HOUSTON, TEXAS, ASSIGNOR TO REED ROLLER BIT COMPANY, OF HOUSTON, TEXAS, A CORPORATION OF TEXAS ROLLER Application filed July 25,

This invention relates to deep well drilling apparatus and more particularly to cutters for roller bits.

The roller bits now in use efficiently penetrate rock formations, because the cutters thereof strike blows, whereby the formation is chipped, and the chips are removed by the slush forced through the drill stem.

The operation of the conventional rock bit in hard and sticky formations, such as shales, is not efficient, because such formations cling to the roller cutters and completely fill the valleys between the cutting teeth. In the language of the drill field, the roller cutters are balled up.

This invention has for its object the pro vision of a new and improved roller cutter adapted to penetrate rock formations, and also hard and sticky formations with equal efficiency. More specifically, its object is to provide a cutter which will not become balled up by sticky formations.

The preferred embodiment of the invention is illustrated in the accompanying drawings, wherein Fig. 1 is a side elevation of a side roller cutter; Fig. 2, an end elevation partly in section of said cutter; and Fig. 3, an end elevation partly in section of a cross roller cutter.

The invention will be found particularly useful in what is known in the art as cross roller cutter bits. A bit of this general type is shown by the patent to 'Childs et' al., No. 1,656,471, of January 17th, 1928. It includes side roller cutters ordinarily mounted at an angle to the lon itudinal axis of the head and a set of cross roller cutters extending between and at substantially a right angle to the side roller cutters. It willbe understood, however, that the present invention is not limited to this type of bit.

The side roller cutter shown by Figs. 1 and 2 of the drawings embodies a plurality of circumferentially extending zig zag cutting teeth 1. The valleys 2 between said teeth extend through the periphery of the cutter and are alternately inclined in opposite directions.

The cross roller cutter shown by Fig. 3, embodies teeth 3 and valleys 4:.

CUTTER 1929. Serial No. 380,867.

The efficient cutting operation of this cutter in sticky formations cannot be attributed solely to the fact that the cutting teeth are zig zag. Its eflicient operation is due to the fact that the cutters are zig zag and that the valleys ext-end through the periphery of the cutter. If the valleys were not open at each end the formation would become balled up therein. As the valleys extend through the periphery of the cutter, the cut material is forced through the valleys to either side of the cutter. This passage of the cut materials through the valleys of the cutter is eifected by the great pressure exerted on the bit and the slush playing upon the cutters; and is expedited by the alternate inclination in opposite directions of the valleys of? the cutters.

I claim:

1. A roller cutter having circumferentially extending zig zag cutting teeth, and valleys between said teeth extending through the periphery of said cutter.

2. A roller cutter having circumferentially extending zig zag cutting teeth, and valleys between said teeth, said valleys beingalternately inclined in opposite directions, and extending through the periphery of said outter.

In testimony whereof, I hereunto aflix my signature.

WILLIAM L. CHILD S. 

